Encrypt-Decrypt contacts database entries using Symbian C++

Comments

09 Sep
2009

Article Review by User:Narendrachinni (20090909)

In this article it had explaine about the Encrypt and Decrypt of contact database actually it is very important to keep the contact data securly because we have many important contact details are stored in contact database so we have to encrypt it for that these article had explianed about the program how to encrypt its contact database.Contact Database is being encrypted here which results in non-readable form of contact items in the Phonebook of user's phone.On the other side Contact Database is decrypted to get the readable content back.

Mandardac - capability require

this is really nice article in order to learn how to access device database.

to run it WriteUserData capability is also require.

mandardac 12:53, 17 May 2012 (EEST)

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This article shows how you might encrypt and decrypt the Contacts database using Symbian C++. The code snippet shows only a basic encryption for demonstration purposes. Note also that this implementation is at the database level so that encrypted data would be displayed encrypted in the existing phone book.

Article Metadata

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Platform Security

Signing Required: DevCert

Capabilities: WriteDeviceData

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Article

Created: kiran10182 (28 May 2007)

Last edited: hamishwillee (30 Jan 2012)

Headers Required:

#include <cntdb.h> // CContactDatabse, 
#include <cntitem.h> //CContactItem,CContactItemFieldSet

Library required (mmp file)

LIBRARY   cntmodel.lib  //CContactDatabse, CContactItem, CContactItemFieldSet

Capability required:

Capability       WriteDeviceData

Encrypt Contact Fields

void CEncryptContactContainer::EncryptAll()
{
	CContactDatabase *contactDB = CContactDatabase::OpenL();
	CleanupStack::PushL(contactDB);
 
	TContactIter iter(*contactDB);
	TContactItemId aContactId;
 
//Developer can take Heap based descriptor for large/unknown size of contact items.
	TBuf16<70> aValue; 
 
	const CContactIdArray* contactArray = contactDB->SortedItemsL();
 
	TInt cnt=contactArray->Count();
 
	for(TInt i=0;i<cnt;i++)
	{
		CContactItem* contactItem=NULL;
 
		contactItem= contactDB->OpenContactL((*contactArray)[i]);
		CleanupStack::PushL(contactItem);
 
		CContactItemFieldSet& fieldSet= contactItem->CardFields();
		TInt fieldCount=fieldSet.Count(); // This will give number of contact fields.
 
		for(TInt index=0; index < fieldCount; index++)
		{
			CContactItemField& field = fieldSet[index];
			const CContentType& type = field.ContentType();
			if(!(type.ContainsFieldType(KUidContactFieldBirthday)))
			{
				TPtrC name = contactItem->CardFields()[index].TextStorage()->Text();
				aValue.Copy(name);
				Encrypt(aValue); // Call real encyption here
				contactItem->CardFields()[index].TextStorage()->SetTextL(aValue);
			}
		} //Inner for loop ends here
		contactDB->CommitContactL(*contactItem);
		CleanupStack::PopAndDestroy(contactItem);
	} //Outer for loop ends here
	CleanupStack::PopAndDestroy(contactDB);
}

void CEncryptContactContainer:: Encrypt (TDes& aValue)
{
	for(TInt iCount=0; iCount< aValue.Length();iCount++)
	{
		aValue[iCount]+=3;
	}
}

Decrypt Contact Fields

void CEncryptContactContainer::DecryptAll()
{
	CContactDatabase *contactDB = CContactDatabase::OpenL();
	CleanupStack::PushL(contactDB);
 
	TContactIter iter(*contactDB);
	TContactItemId aContactId;
	TBuf16<70> aValue;
 
	const CContactIdArray* contactArray = contactDB->SortedItemsL();
 
	TInt cnt=contactArray->Count();
 
	for(TInt i=0;i<cnt;i++)
	{
		CContactItem* contactItem=NULL;
 
		contactItem= contactDB->OpenContactL((*contactArray)[i]);
		CleanupStack::PushL(contactItem);
 
		CContactItemFieldSet& fieldSet= contactItem->CardFields();
		TInt fieldCount=fieldSet.Count(); // This will give number of contact fields.
 
		for(TInt index=0; index < fieldCount; index++)
		{
			CContactItemField& field = fieldSet[index];
			const CContentType& type = field.ContentType();
			if(!(type.ContainsFieldType(KUidContactFieldBirthday)))
			{
				TPtrC name = contactItem->CardFields()[index].TextStorage()->Text();
				aValue.Copy(name);
				Decrypt(aValue);
				contactItem->CardFields()[index].TextStorage()->SetTextL(aValue);
			}
		} //Inner for loop ends here
		contactDB->CommitContactL(*contactItem);
		CleanupStack::PopAndDestroy(contactItem);
	} //Outer for loop ends here
	CleanupStack::PopAndDestroy(contactDB);
}

void CEncryptContactContainer:: Decrypt (TDes& aValue)
{
	for(TInt iCount=0; iCount< aValue.Length();iCount++)
	{
		aValue[iCount]-=3;
	}
}

• Here simple encryption is used to give an idea. Developer can use more complex Encyption-Decryption algorithms.